Apparatus and method for producing expanded metal

ABSTRACT

An elongated metal sheet is continuously advanced in a longitudinal direction past a plurality of toothed cutting and deforming wheels rotated about axes perpendicular to the direction of sheet advancement. The teeth of each wheel both shear and deform the sheet, to produce a line of spaced apart openings. The wheels are staggered laterally, to produce laterally spaced apart lines of openings in the sheet. Each wheel is one half tooth pitch out of phase with the wheels immediately preceding and succeeding it, so that each opening in the sheet is located between two successive openings in an adjacent line. The wheels are rotated by a transmission including a sprocket rotatable with each wheel and a chain meshing with all the sprockets. An idler sprocket adjustable toward and away from the plane containing the axes of rotation of the wheels, and meshing with the chain between each two successive sprockets, permits the phase relationship between each two successive wheels to be adjusted without affecting the phase relationship between any other pair of successive wheels. Two sets of wheels may be provided to produce two longitudinally extending areas in the sheet, furnished with openings, separated by a longitudinally extending imperforate area.

United States Patent 91 Felsenthal APPARATUS AND METHOD FOR PRODUCING EXPANDED METAL [75] Inventor: Robert M. Felsenthal, Westport,

Conn.

[73] Assignee: Exmet Corporation, Bridgeport,

Conn.

[22] Filed: Feb. 8, 1971 [21] Appl. No.: 113,402

[52] US. Cl. 29/6.1 [51] Int. Cl B2ld 31/04 [58] Field of Search 29/6.l

[56] References Cited UNITED STATES PATENTS 1,526,769 2/1925 Bradford 29/61 3,276,096 10/1966 McAleer et a1. 29/6.l 1,949,966 3/1934 Kessler 29/6.l 1,443,555 1/1923 Baker 29/6.l 1,178,853 4/1916 Hyde 29/6.l X 2,468,595 4/1949 Elmendorf 29/6.l

Primary Examiner-Andrew R. Juhasz Assistant Examiner-Leon Gilden Attorney-Breitenfeld & Levine LI a o Q A, Q j

[451 Sept. 25, 1973 [57] ABSTRACT An elongated metal sheet is continuously advanced in a longitudinal direction past a plurality of toothed cutting and deforming wheels rotated about axes perpendicular to the direction of sheet advancement. The teeth of each wheel both shear and deform the sheet, to produce a line of spaced apart openings. The wheels are staggered laterally, to produce laterally spaced apart lines of openings in the sheet. Each wheel is one half tooth pitch out of phase with the wheels immediately preceding and succeeding it, so that each opening in the sheet is located between two successive openings in an adjacent line. The wheels are rotated by a transmission including a sprocket rotatable with each wheel and a chain meshing with all the sprockets. An idler sprocket adjustable toward and away from the plane containing the axes of rotation of the wheels, and meshing with the chain between each two successive sprockets, permits the phase relationship between each two successive wheels to be adjusted without affecting the phase relationship between any other pair of successive wheels. Two sets of wheels may be provided to produce two longitudinally extending areas in the sheet, furnished with openings, separated by a longitudinally extending imperforate area.

8 Claims, 6 Drawing Figures PAYENTED 2 7 SHEEI 1 0F 3 INVENTOR:

205627 MFLSIUZW4L BY IATTORNEYS FIG. 3

APPARATUS AND METHOD FOR PRODUCING EXPANDED METAL This invention relates to metallic sheet material commonly known as expanded metal" in which successive staggered rows of openings are defined by sheared strands pressed out of the original plane of the sheet. In particular, the invention relates to an improved apparatus and method for producing such material.

In one procedure often employed for making expanded metal, a toothed punch is reciprocated with respect to a shear plate and laterally shifted between shearing operations, while the metal sheet to be treated is advanced stepwise, in a direction perpendicular to the plane in which the punch moves, to subject successive areas of the sheet to the shearing action of the punch. Problems presented by this conventional procedure involve the fact that the sheet must be moved and stopped between each two successive operations of the punch. As a result, the speed of operation of the apparatus is limited, since it takes time to move the sheet from a stand-still condition and then bring it to a halt, and the continuous accelerations and decelerations of the sheet and the parts which move it cause a good deal of wear to the machine parts.

Another problem arises when expanded metal for certain end uses is being made. For example, electrodes of electrochemical cells often comprise an expanded metal sheet the openings and surface of which carry a chemically active powder. Such a sheet may not have openings over its entire surface. Instead, one margin of the sheet is left imperforate to serve as the terminal of the electrode. To provide each sheet with an imperforate margin, reciprocation of the punch must be halted at regular intervals, during which the sheet continues its advance, after which reciprocation of the punch resumes. The necessity for stopping the punch obviously lowers the efficiency of the expanding operation. It may be mentioned that the expanded metal is severed transversely to produce the individual electrode sheets.

It is an object of the present invention to overcome these problems by providing an apparatus and method for producing expanded metal which are much faster than the conventional approach described above, and involve much less wear on the machine parts. I

It is another object of the invention to provide such an apparatus and method in which both the sheet being treated and the expanding means move continuously, in contrast to the intermittent and reciprocal movement of the sheet and punch, respectively, in conventional apparatus.

It is a further object of the invention to provide such an apparatus and method whereby the openings are formed in the sheet along lines parallel to the direction of sheet advancement, rather than transversely thereto as in the conventional system. As a result, a longitudinally extending'imperforate region of the sheet may be provided without discontinuing the expanding opera tion.

It is an additional object of the invention to provide such an apparatus and method in which rotating toothed wheels are employed to perform the expanding operation, and in which the phase relationship of each succeeding pair of wheels may be adjusted without affecting the phase relationship between all other pairs of succeeding wheels.

It may be mentioned that in conventional machines for making expanded metal lath, a reciprocable punch as described above is not used. Instead, a cutting wheel is furnished which provides a metal sheet with lines of discontinuous slits, the slits in each two adjacent lines being staggered. Thereafter, the edges of the sheet are grasped and pulled away from each other. As a result, the strands of metal defined by the slits are deformed and bent out of the plane of the sheet, and the lateral dimension of slits is enlarged to form openings in the sheet. It has been suggested, in US. Pat. No. 1,526,769, that instead of pulling the slit sheet laterally, the sheet, after slitting, be subjected to the action of toothed expanding wheels which deform the strands defined by the slits.

In either case, a two step operation is involved, namely, first slitting and then expanding. It is an object of this invention to provide a method and apparatus for creating expanded metal in one step using a plurality of wheels each of which both cuts and deforms the metal sheet.

The usual commercial methods of making expanded metal either suffer the speed penalty of reciprocating equipment or if rotary in nature are not adaptable to making expanded and imperforate joined portions.

Additional objects and advantages of the present invention will be apparent from the following description in which reference is made to the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of an apparatus for producing expanded metal according to the present invention;

FIG. 2 is a plan view of the apparatus;

FIG. 3 is a vertical cross-sectional view taken along line 33 of FIG. 2;

FIG. 4 is a vertical cross-sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a fragmentary exploded perspective view of the apparatus; and

FIG. 6 is a fragmentary perspective view of an alternative embodiment of the apparatus.

The apparatus chosen to illustrate the present invention is intended to expand an elongated metal sheet 9, and includes a stationary frame 10 having a pair of upper horizontal members 11 (FIGS. 1 and 2) and a pair of lower horizontal members 12. Extending horizontally between upper members 11 are a plurality of shafts l3 and 14, journalled for rotation in suitable bearings (not shown) carried by members 11. Extending horizontally between lower members 12 are a plurality of shafts 15 journalled for rotation in suitable bearings (not shown) carried by members 12. The number of shafts 15 equal the number of shafts l3 and 14, and one shaft 15 is located in vertical alignment with each shaft 13 and 14.

Each of the shafts l3 and 14 has fixed to it, between members 11, a toothed cutting and deforming wheel 18, 19, and 20, as well as a roller 21 adjacent to the wheel. The periphery of each wheel 18-20 extends beyond the periphery of its respective roller 21 and is serrated to define teeth 22.

Fixed to each shaft 15 is a roller 25 spaced from roller 21 a distance about equal to the thickness of metal sheet 9. As a result, sheet 9 is held firmly between rollers 21 and 25 during the expanding operation. One end edge 26 of each roller 25 defines a shear edge and is arranged in shearing relationship with the teeth 22 of its respective wheel 18-20. The portion of shear edge 26 intersecting the vertical line between the axis of shafts l4 and overlaps a portion of the adjacent teeth 22 of its respective wheel, but does not overlap the radially innermost part of the valley between each two adjacent teeth. As a result, the wheels 18-20 and their respective rollers do not completely shear the metal sheet 9 passing between them. Instead, as the wheels rotate and sheet 9 moves past them, teeth 22 of each wheel create a line of discontinuous cuts in the sheet, and simultaneously push downwardly the short strands of metal defined by the cuts to produce a line of openings in the sheet.

Wheels 18-20 are not all arranged in the same vertical plane. Instead, they are staggered laterally, as may be seen in FIG. 2, so that the line of openings produced by each wheel is laterally offset from the line of openings produced by every other wheel. Thus, as shown in FIG. 3, as sheet 9 moves longitudinally through the apparatus, wheel 18 produces openings 27, wheel 19 produces openings 28, and wheel 20 produces openings 29. It will be seen that the angular positions of the wheels is such that wheel 19 is one half tooth pitch out of phase with wheels 18 and 20, as a result of which each of the openings 28 produced by wheel 19 is located between two successive openings 27 and between two successive openings 29.

One end of each shaft 14 projects outwardly beyond its respective frame member 11, and both ends of shaft 13 project beyond members 11. An electric motor 32 beneath shaft 13 drives that shaft through gearing (not shown) interconnecting the motor shaft and one projecting end of shaft 13. Shafts 14 are rotated by a transmission including sprockets 33, 34, and 35 mounted on the other projecting end of shaft 13 and the projecting ends of shafts 14. A single continuous non-stretchable, but flexible, chain 36 is trained about all the sprockets 33-35, and also about an idler sprocket 37 below sprockets 33-35. Idler sprocket 37 is rotatably mounted on one end of an arm 38, the other end of which is pivoted at 39 to machine frame 10. A tension spring 40 connected at one end to arm 38 and at the other to frame 10 constantly urges sprocket 37 downwardly to tension the lower run of chain 36. The upper run of chain 36 meshes with all the sprockets 33-35 and thereby transmits the rotation of shaft 13 to each of shafts 14.

As mentioned above, wheels 18-20 should have a particular angular phase relationship so that openings 27-29 in sheet 9 have the desired relationship. It is important, therefore, that the wheels 18-20 be rotationally adjustable with respect to each other, so that the phase of each wheel can be adjusted with respect to the wheels immediately preceding and succeeding it. However, since chain 36 engages all the sprockets 33-35, and it cannot stretch, a problem is presented as to how such adjustability can be achieved.

According to the present invention, this problem is overcome by providing some slack in the upper run of chain 36, between each two successive sprockets, when the chain is initially assembled with the sprockets. An idler sprocket 41 engages the chain between sprockets 33 and 34, and another idler sprocket 42 engages the chain between sprockets 34 and 35. Idler sprockets 41 and 42 are rotatably mounted on the ends of arms 43 and 44, respectively, the opposite end of each arm being pivoted at 45 to frame 10. As a result of this arrangement, idler sprockets 41 and 42 are adjustable toward and away from the plane containing the axes of rotation of shafts l3 and 14. An adjusting screw 46, having a knob 47, is threadably supported within a block 48 fixed to frame 10, and engages each of arms 43 and 44, to hold the latter, in any desired position of adjustment, against the tendency of the chain to straighten out and raise the sprocket carried by the arm.

To adjust the phase relationship between the first two successive wheels, namely, wheels 18 and 19, arm 43 and hence sprocket 41 are moved up or down by operating the proper adjusting screw 46. Due to this movement of arm 43, the position of chain 36 between sprockets 33 and 34 is altered, and wheels 18 and 19 are rotated in opposite directions. In this way, any desired phase relationship between wheels 18 and 19 can be achieved. It may be mentioned that during this adjustment wheel 20 will be rotated in the same direction as wheel 19, but this is unimportant since only wheels 18 and 19 are being adjusted at this time. Now, to adjust the phase relationship between the next pair of successive wheels, namely, wheels 19 and 20, arm 44 and hence sprocket 42 are moved up or down by operating the proper adjusting screw 46. Due to this movement of arm 44, the position of chain 36 between sprockets 34 and 35 is altered, and wheels 19 and 20 are rotated in opposite directions to bring about any desired phase relationship between them. This rotation of wheel 19 has no effect on the previously adjusted phase relationship between wheels 18 and 19, since wheel 18 rotates with wheel 19 and the chain length between them remains the same due to the fixed position of the rotation axis of sprocket 41. Thus, no matter how many wheels are employed, the phase relationship between each successive pair of wheels can be adjusted without affecting the phase relationship between any other pair of successive wheels.

From the above description, and reference to FIG. 5, it is believed that operation of the apparatus will be understood. An elongated sheet 9 of metal to be treated is initially threaded through the apparatus. The sheet may come from a large supply roll, not shown. Motor 32 is turned on, and as sheet 9 moves longitudinally and continuously through the apparatus, by the action of wheels 18-20 and rollers 21 and 25, wheels 18-20 serve to expand the sheet. As indicated in FIG. 2, the expansion begins along one longitudinal edge of the sheet, where wheel 18 operates, but terminates short of the other longitudinal edge, since the cutting and deforming wheels do not extend all the way across the sheet. As a result, a margin 51 (FIG. 5) along one edge of the sheet remains unexpanded. Although for convenience of illustration only three wheels 18-20 have been shown in the drawings, in practice many more will ordinarily be employed, say, 35 or 40 wheels. The greater the number of wheels, of course, the wider will be the region of the sheet which is expanded. If desired, a sufiicient number of wheels may be provided to extend across the entire width of the metal sheet, in which case the entire sheet will be expanded. As the expanded metal leaves the machine, it may pass between a vertically reciprocable chopper blade 52 and a platen 53 which severs it, along lines perpendicular to its direction of advancement, into individual pieces 54 suitable for use, for example, in making electrodes.

In an alternative embodiment of the invention, shown in FIG. 6, all parts are identical to those described with reference to FIGS. 1-5, except that each of the shafts l3 and 14 carries two cutting and deforming wheels 20 and 20 spaced axially apart. Thus, two sets of wheels are provided, the first wheel of-each set engaging a longitudinal edge of the sheet 9', and the subsequent wheels of each set being staggered toward the center of the sheet. Roller 25 beneath each shaft 14 may have a length equal to the spacing between the two wheels carried by that shaft so that its opposite ends serve as the shear edges for those wheels.

The two sets of wheels of F IG. 6 may meet at the center of the sheet 9 in which case the entire sheet will be expanded. However, at their closest, the two sets may be spaced apart to leave an unexpanded region 57 along the longitudinal center of the sheet. As the expanded sheet leaves the machine, a cutting device, such as a circular rotating blade 58 may slit the sheet longitudinally in the region 57, and a vertically reciprocable chopper blade 59 may sever it into individual pieces 60 and 61. Each of these pieces has an unexpanded margin 62. Thus, with the apparatus of the alternative embodiment, twice as many individual expanded metal pieces may be produced, per unit time, than with the apparatus of FIGS. 1-5.

The invention has been shown and described in preferred form only, and by way of example, and many variations may be made in the invention which will still be comprised within its spirit. It is understood, therefore, that the invention is not limited to any specific form or embodiment except insofar as such limitations are included in the appended claims.

What is claimed is:

1. Apparatus for producing an expanded metal sheet, comprising:

a plurality of toothed wheels,

a shear edge in shearing relation to each of said wheels, an elongated sheet to be treated being continuously advanced in a longitudinal direction between said wheels and shear edges,

means for continuously rotating said wheels about axes perpendicular to said'longitudinal direction so that the teeth of each wheel shear the sheet to produce a series of longitudinally aligned spaced apart openings,

said wheels being staggered laterally so that the line of openings produced by each wheel is laterally offset from the lines of openings produced by the other wheels, and

said means for rotating said wheels includes a sprocket rotatable with each of said wheels, asingle chain meshing with all of said sprockets, and means engaging said chain between each two successive sprockets for adjusting the angular phase relationship between each two successive wheels,

6 while said chain and sprockets remain meshed, without affecting the phase relationship between any other pair of successive wheels,

so that the angular positions of said wheels can be arranged such that each wheel is one half tooth pitch out of phase with the wheels immediately preceding and succeeding it in the longitudinal direction, whereby each opening in the sheet will be located between two successive openings in an adjacent line of openings.

2. Apparatus as defined in claim 1 wherein said lastnamed means includes an idler sprocket'meshing with said chain and rotatable about an axis which is adjustable toward and away from the plane containing the axes of rotation of said wheels, and means for fixing said idler sprocket axis in any desired position of adjustrnent.

3. Apparatus as defined in claim 1 wherein said chain has one run moving generally in one direction and another run moving generally in the opposite direction, said one run engaging all of said sprockets, an idler sprocket meshing with said other run, and resilient means urging said idler sprocket away from said one run, thereby tensioning said other run.

4. Apparatus as defined in claim 1 wherein each of said shear edges is defined by a roller rotatable about an axis parallel to the axis of rotation of its respective wheel.

5. Apparatus as defined in claim 1 including means for severing the sheet, after it passes the last of said wheels, along lines perpendicular to said longitudinal direction of advancement.

6. Apparatus as defined in claim 1 including two sets of said toothed wheels, one wheel of each set being rotatable about the same axis as a corresponding wheel of the other set, said wheels of each set being staggered laterally, and the closest spacing between wheels of the two sets being greater than the spacing between adjacent lines of openings produced by said wheels, whereby the metal sheet produced by the apparatus has two longitudinally extending areas furnished with openings separated by an imperforate longitudinally extending area.

7. Apparatus as defined in claim 6 wherein each of said shear edges is defined by a roller rotatable about an axis parallel to the axis of rotation of its respective wheel, said shear edges associated with each two corresponding wheels of said two sets being defined by opposite ends of the same roller.

8. Apparatus as defined in claim 6 including means for severing the sheet, after it passes the last of said wheels, along lines perpendicular to said longitudinal direction of advancement, and means for severing the sheet in its imperforate area along a line parallel to said longitudinal direction of advancement. 

1. Apparatus for producing an expanded metal sheet, comprising: a plurality of toothed wheels, a shear edge in shearing relation to each of said wheels, an elongated sheet to be treated being continuously advanced in a longitudinal direction between said wheels and shear edges, means for continuously rotating said wheels about axes perpendicular to said longitudinal direction so that the teeth of each wheel shear the sheet to produce a series of longitudinally aligned spaced apart openings, said wheels being staggered laterally so that the line of openings produced by each wheel is laterally offset from the lines of openings produced by the other wheels, and said means for rotating said wheels includes a sprocket rotatable with each of said wheels, a single chain meshing with all of said sprockets, and means engaging said chain between each two successive sprockets for adjusting the angular phase relationship between each two successive wheels, while said chain and sprockets remain meshed, without affecting the phase relationship between any other pair of successive wheels, so that the angular positions of said wheels can be arranged such that each wheel is one half tooth pitch out of phase with the wheels immediately preceding and succeeding it in the longitudinal direction, whereby each opening in the sheet will be located between two successive openings in an adjacent line of openings.
 2. Apparatus as defined in claim 1 wherein said last-named means includes an idler sprocket meshing with said chain and rotatable about an axis which is adjustable toward and away from the plane containing the axes of rotation of said wheels, and means for fixing said idler sprocket axis in any desired position of adjustment.
 3. Apparatus as defined in claim 1 wherein said chain has one run moving generally in one direction and another run moving generally in the opposite direction, said one run engaging all of said sprockets, an idler sprocket meshing with said other run, and resilient means urging said idler sprocket away from said one run, thereby tensioning said other run.
 4. Apparatus as defined in claim 1 wherein each of said shear edges is defined by a roller rotatable about an axis parallel to the axis of rotation of its respective wheel.
 5. Apparatus as defined in claim 1 including means for severing the sheet, after it passes the last of said wheels, along lines perpendicular to said longitudinal direction of advancement.
 6. Apparatus as defined in claim 1 including two sets of said toothed wheels, one wheel of each set being rotatable about the same axis as a corresponding wheel of the other set, said wheels of each set being staggered laterally, and the closest spacing between wheels of the two sets being greater than the spacing between adjacent lines of openings produced by said wheels, whereby the metal sheet produced by the apparatus has two longitudinally extending areas furnished with openings separated by an imperforate longitudinally extending area.
 7. Apparatus as defined in claim 6 wherein each of said shear edges is defined by a roller rotatable about an axis parallel to the axis of rotation of its respective wheel, said shear edges associated with each two corresponding wheels of said two sets being defined by opposite ends of the same roller.
 8. Apparatus as defined in claim 6 including means for severing the sheet, after it passes the last of said wheels, along lines perpendicular to said longitudinal direction of advancement, and means for severing the sheet in its imperforate area along a line parallel to said longitudinal direction of advancement. 